Does the 50mm f/1.8G and D work on Nikon D3100?

I'm a beginner, so yeah. Also is 50mm good for street photography(B&W) and portraits.

You need to look to see if the lens is an AF-S lens or not. Only AF-S lenses work on your entry level D3100

Here is a link to all the available Nikkor lenses.

http://www.nikonusa.com/...index.page

The 50mm f/1.8D won't autofocus on your D3100, but the 50mm f/1.8G will.

As for quality, be inspired by some of these amazing images taken with a 50mm lens and a Nikon D3100 exactly like yours.

You need the 50mm f/1.8 G. The D will not autofocus, but the G will. Both will 'work' in the sense that it will capture shots, but only the G will autofocus.
I have a 50mm 1.8 G and I'm in love with it. Sharp. Sharp. Sharp!
Have fun!